I think the idea would be to use the server side cheat detectio to decide which players need to be forced to install the client side cheat detection, basically.

You're right of course, if there's no $$$ to be made from people who won't buy the game if it has client-side anticheat, then why would they develop a whole second system just for people like me who don't want to run this crap, but want to play the game enough that they'll run it anyway?